DE 697 07 536 T2 describes a linear position-detection device of the induction type, which generates alternating current signals on the basis of excitation by means of a single-phase alternating current signal and outputs said signals which indicate multi-phase amplitude function characteristics in reaction to a linear position to be detected. For this purpose, the linear position-detection device has a cylindrically shaped winding section and a rod-shaped variable magnetic coupling section which is arranged between the windings of the winding section at a suitable distance.
DE 201 15 060 U1 describes an actuator which does not have a camshaft and has the purpose of activating a poppet valve of an internal combustion engine with a tappet which is moved in an oscillating fashion and is coupled to the poppet valve, wherein a target ring which is slotted at least once and is embodied as a separate, prefabricated part which is composed of a material on an FE basis or of a ferritic material is attached to the outer circumference of the tappet. A sensor which surrounds the tappet and operates inductively and at low frequencies determines the position of the tappet.
DE 41 20 643 A1 relates to a friction clutch for motor vehicles having a clutch plate which can be clamped in between two components and is seated in a rotationally fixed fashion on a transmission shaft, a clutch spring for clamping in the clutch plate between the two components, a clutch-activation device having a slave device near to the clutch, a master device remote from the clutch and a transmission device arranged between them, wherein a travel sensor, which is arranged in or on the slave cylinder, is arranged in a slave device near to the clutch. For the purpose of capacity detection of a travel signal, an annular piston is provided with an electrically conductive coating on its outer circumference. The annular piston is accommodated in a projection which forms a capacitor with the coating of the piston.
DE 10 2006 031 139 A1 relates to a device for the contactless and wear-free measurement of the absolute linear position with planar coils of equipment elements, machine elements or activation elements in a range from 10 mm to 200 mm, wherein this element can itself perform the function of the rotor. The losses of the electromagnetic field which arise as a result of eddy currents in the rotor are measured on two planar triangular coils which are arranged differentially in a plane. These losses are proportional to the area of the triangular coils covered by the rotor and are therefore proportional to the absolute position. A second pair of coils is arranged in a second plane, which compensates for changes in the distance from the rotor.
DE 10 2013 214 358 A1 relates to a measuring device for a manual shift transmission for sensing the position of a shifting shaft in relation to a housing comprising a sensor arrangement and a sensor target, wherein the sensor arrangement comprises an inductive sensor by means of which a distance between the inductive sensor and the sensor target is detected, and the sensor target is fabricated from a conductive material, wherein the shape of the sensor target is configured such that the distance between the inductive sensor and the sensor target varies as a function of the position of the shifting shaft in relation to the housing.
U.S. Pat. No. 4,623,840 A describes an actuator which comprises a cylindrical body on the outer surface of which a coil is formed and a piston which serves as a core is arranged in the body. Displacement of the piston can be detected by means of a detection circuit, as a result of a change in the coil induction owing to the displacement of the piston.